Cutting and/or forming plate workpieces

ABSTRACT

A method for processing a plate workpiece supported on a workpiece support. The method includes moving a tool die and a tool punch along a stroke axis and toward a processing position above a support plane of the workpiece support. The processing position corresponds to a region of the plate workpiece having a formed shape, which extends upwardly from the support plane of the workpiece support.

CROSS REFERENCE OF RELATED APPLICATION

Under 35 U.S.C. §119, the application claims the benefit of EuropeanApplication No. EP 08 018 315.5, filed Oct. 20, 2008. The content ofthis priority application is hereby incorporated by reference in itsentirety.

TECHNICAL FIELD

This invention relates to the processing, e.g., the cutting and/orforming, of plate workpieces, such as metal sheets, and tools configuredto do such processing.

BACKGROUND

Flexible processing of metal sheets by cutting and/or forming can beperformed by means of punching/forming machines. Some known machinespermit various workpiece processing operations to be performed on thesame machine tool. For example, sheet metal parts may be cut free from asheet metal composite and forming operations may be performed on thosesheet metal parts. An example of such a machine tool is the TruPunch®5000 punching machine offered by Trumpf Werkzeugmaschinen GmbH+Co. KGwhich has mono-tool holders. The mono-tool holders support a single toolthat includes a tool punch and a tool die. Further tools can be takenfrom a tool magazine and inserted as alternative tools into themono-tool holders as and when required.

The mono-tool holders have a tool punch holder that can be raised andlowered by means of a hydraulic stroke drive, and a stationary tool dieholder. A workpiece table serves to support a metal sheet that is to beprocessed. Workpiece processing is effected by lowering the tool punchholder together with a tool punch secured thereto onto the metal sheetsupported on the workpiece table. The metal sheet is acted upon by thetool punch on the one side and by the tool die on the other.

Where a workpiece is subject to a forming operation, for example byroll-forming, in a region that was previously processed by a punchingoperation, the punched contour, produced by the punching operation, maychange as a result of the forming operation, i.e., the punched contourmay no longer correspond to the original contour produced by thepunching operation.

SUMMARY

In general, this invention relates to the processing, e.g., the cuttingand/or forming, of plate workpieces, such as metal sheets, and toolsconfigured to do such processing.

One aspect of the invention features a plate workpiece processingmethod. The method includes supporting a plate workpiece on a workpiecesupport. The plate workpiece has a region with a formed shape thatextends upwardly from a support plane of the workpiece support. Themethod also includes moving a tool die and a tool punch along a strokeaxis, toward a processing position above the support plane, and intocontact with the plate workpiece in the region of the formed shape,thereby processing the plate workpiece in the region of the formedshape.

In some embodiments, the method also includes forming, e.g., byroll-forming, the formed shape in the plate workpiece. The forming canperformed while the plate workpiece is supported on the workpiecesupport. In some cases, following the forming of the formed shape, themethod also includes moving the plate workpiece along the support planetoward a position in which the formed shape intersects the stroke axis.

The method can also include moving the tool punch and the tool die to ahome position in which the tool die does not project upwards beyond thesupport plane and the tool punch does not project downwards beyond thesupport plane.

In some cases, the tool die is supported in a tool die holder and thetool punch is supported in a tool punch holder, and moving the tool dieand the tool punch along the stroke axis includes moving the tool dieholder and the tool punch holder along the stroke axis.

The tool die and the tool punch can be moved independently of each otheralong the stroke axis.

In some embodiments, the method includes detecting the presence of thetool die in the processing position.

The method can also include moving the plate workpiece along the supportplane toward a position in which the formed shape intersects the strokeaxis. The movement of the plate workpiece can be carried out by means ofa coordinate guide.

In another aspect, a computer readable medium has encoded thereonsoftware for processing a plate workpiece supported on a workpiecesupport. The software includes instructions for moving a tool die and atool punch along a stroke axis and toward a processing position above asupport plane of the workpiece support. The processing positioncorresponds to a region of the plate workpiece having a formed shape,which extends upwardly from the support plane of the workpiece support.

Another aspect of the invention provides a plate workpiece processingtool that includes a workpiece support, a tool punch, a tool die, and acontrol unit that is configured to control movements of the tool punchand the tool die along a stroke axis. The workpiece support defines asupport plane for supporting a workpiece. The tool punch and the tooldie are displaceable, along the stroke axis, to a processing positionabove the support plane of the workpiece support such that the toolpunch and the tool die are capable of processing a region of a workpiecethat has a formed shape that extends upwardly from the workpiecesupport.

In some embodiments, the tool also includes a tool punch holder forsupporting the tool punch, a tool die holder for supporting the tooldie, and a tool drive in communication with the control unit. Thecontrol unit is configured to control movements of the tool punch holderand the tool die holder, along the stroke axis, via the tool drive.

In some cases, the tool die is in the shape of a pyramidal frustum or aconical frustum.

The tool can also include a sensor unit that is arranged to sense thepresence of the tool die in the processing position.

In some embodiments, the tool includes a coordinate guide that isoperable to control movements of a workpiece along the support plane.

The workpiece support can be a bristle carpet, which forms the supportplane.

The control unit can include a memory storage that includes storedworkpiece data corresponding to a formed shape in a workpiece. Thecontrol unit can be configured to control movements of the tool punchand the tool die based, at least in part, on the stored workpiece data.

In yet another aspect, the invention features a method for processing aplate workpiece supported on a workpiece support, in which a tool punchand a tool die are moved to a processing position above or below asupport plane on the workpiece support in order to process the workpiecein a region of a formed shape projecting upwards or downwards beyond theworkpiece support.

By moving the tool die or the tool punch to a processing position aboveor below the support plane, processing by cutting and/or forming may becarried out on formed shapes of the workpiece. In some cases, the tooldie may be raised or lowered until a support face of the tool diereaches an underside of the formed shape and supports the formed shapeof the workpiece while it is being acted upon by the tool punch. Thetool die may, for example, be positioned in the processing positionbefore the tool punch is lowered onto the formed shape of the workpiece.Alternatively, the tool punch and the tool die can be movedsynchronously in order to process the workpiece at the processingposition. The location of the processing position above or below theworkpiece plane or support plane is variable and depends on how far theformed shape produced in the workpiece, or rather the region that is tobe processed in that formed shape, projects beyond the workpiece plane.

In some embodiments, the formed shape is made in the workpiece, while itis resting on the workpiece support, by forming (e.g., roll-forming).The formed shape may then be processed by punching and/or rim holes orscrew-threads may by formed in the formed shape and/or additionaldownwardly or upwardly formed shapes may be made in the formed shape. Itwill be appreciated that it is not imperative that the forming of theformed shape is performed on the machine tool. As an alternative, it isalso possible for a workpiece having one or more formed shapes to beloaded onto the workpiece support.

In some cases, the tool punch and the tool die are taken to a homeposition in which the tool die does not project upwards and the toolpunch does not project downwards beyond the support plane. To position aregion of a workpiece that is to be processed—in the present case at theformed shape—in a position on the workpiece support where the tool dieand the tool punch are situated, the workpiece may be moved along theworkpiece support by means of a coordinate guide. To prevent collisionof the workpiece with the tool die and/or the tool punch during thatmovement, they may be retracted to a home position in which, forexample, the support face of the tool die is flush with the workpiecesupport or is disposed below the workpiece support. To facilitatemovement of the workpiece along the workpiece support, castors or abristle carpet, for example, may be provided on the workpiece support.

In some cases, the tool die is supported in a tool die holder and thetool punch is supported in a tool punch holder, which holders are movedtowards each other along the stroke axis independently of each other forprocessing of the workpiece. The independent movement of the tool punchand the tool die by means of two independent drives makes it possible,for example, for a punching operation to be carried out above or belowthe workpiece plane. For example, first the tool die can be positionedin the processing position, and then, for processing by punching, thetool punch can be lowered onto the tool die to process the workpieceresting on the support face of the tool die.

In some embodiments, the presence of the tool punch and/or the tool diein the processing position is detected. The presence of the tool die orthe tool punch in the processing position can be detected with precisionto enable reliable processing of the workpiece and to inhibit (e.g.,prevent) the workpiece from being unintentionally moved downwards beyondthe processing position by the tool punch, and thereby possibly beingdeformed in addition, and/or to inhibit (e.g., prevent) the workpiecefrom being partially lifted from the workpiece support by the tool die.Detection can be carried out by means of a control device capable ofaccessing data on the formed shapes made in the workpiece, especially onthe spacing of the underside of the region to be processed relative tothe workpiece plane. In addition or as an alternative, it is alsopossible for sensors, e.g., pressure sensors, capacitive sensors, etc.,to be provided in order to monitor the attainment of the processingposition by the tool die or the tool punch.

In some examples, when the workpiece is being processed in a processingposition that is located below the support plane, a tool shank of thetool punch is disposed above the support plane. The tool shank, i.e.,the region of the tool punch that is supported in the tool punch holder,widens outwards and therefore it may be desirable if that region is notbrought into engagement with formed shapes of small dimensions. It maytherefore be advantageous for the tool punch to extend below the supportplane by only the punch head, which adjoins the tool shank and has asmaller width. In particular, it is possible to select a tool punch thatis suitable for processing a given formed shape. The punch head of theselected tool punch can have a length that is greater than the distancebetween the support plane and the respective processing position belowthe support plane, i.e., the length of the punch head or the tool punchand the processing position in the stroke direction are so coordinatedwith each other that the tool shank remains above the workpiece supportduring processing.

A further aspect of the invention provides a plate workpiece processingtool that includes a workpiece support, a tool punch, and a tool die.The processing tool also includes a control unit that isconfigured/programmed to move the tool punch and the tool die along thestroke axis to a processing position above or below a support plane ofthe workpiece support to process a formed shape of a workpiece thatprojects upwards or downwards beyond a support plane on the workpiecesupport. Where a punching operation is to be performed on a workpiece ina region above or below the support plane or workpiece plane, generallythe tool die is positioned in the processing position first and then thetool punch is lowered towards the stationary tool die. Alternatively,punching can be performed by pressing the tool die against thestationary tool punch from below with a stroke movement or bysimultaneously moving both the tool punch and the tool die towards eachother along the stroke axis.

In some embodiments, the processing tool also includes a tool punchholder for supporting the tool punch, a tool die holder for supportingthe tool die, and a tool drive by means of which the tool punch holderand the tool die holder are movable along the stroke axis. The tooldrive may include two drive units that can be actuated independently ofeach other, i.e., for driving the tool punch holder and the tool dieholder independently. The tool punch holder and the tool die holder mayin this case be in the form of mono-tool holders to and on whichdifferent tools may be selectively secured and supported.

In some cases, the tool die is in the shape of a pyramidal frustum or aconical frustum and has a support face for supporting the workpiece.Such a geometry of the tool die can be beneficial for avoiding collisionwith the peripheral regions of the formed shape as the tool die is beingraised above the workpiece plane and before the tool die reaches theprocessing position. For that purpose, the tool die can be taller thancustomary tool dies and can be configured to have a smaller supportface. The tool die may also have another, asymmetric, geometry that isadapted to the geometry of the formed shape that is to be processed. Ifa punching die is used as the tool die, one or more apertures forengagement of a punch head may be formed at the top surface.

In some embodiments, the processing tool includes a sensor unit fordetecting the presence of the tool punch and/or the tool die in theprocessing position. The sensor unit can include one or more pressuresensors, optical sensors, etc. Alternatively or additionally, the sensorunit can include capacitive sensors for measuring the potential betweenworkpiece and tool die or tool punch. Before processing of the workpieceis carried out, the measurement data provided by the sensors can becompared with data, relating to the type and size of the formed shape,that is stored in the control unit.

Other aspects, features, and advantages of the invention will beapparent from the description, the drawings, and the claims. Thefeatures mentioned above and the features set forth hereinafter may alsobe used individually or a plurality thereof may be used in any desiredcombination. The embodiments shown and described are not to beunderstood as forming a definitive list, but rather are of the nature ofexamples for illustrating the invention.

DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic illustration of a plate workpiece processing tool.

FIGS. 2 a-c illustrate a punching operation being performed on anupwardly formed shape on a workpiece using the plate workpieceprocessing tool of FIG. 1.

FIGS. 3 a-c illustrate a punching operation begin performed on adownwardly formed shape on a workpiece using the plate workpieceprocessing tool of FIG. 1.

DETAILED DESCRIPTION

FIG. 1 shows a plate workpiece processing tool for cutting and/orforming plate workpieces in the form of a punching/forming machine 1 forprocessing metal sheets. The punching/forming machine 1 has a C-shapedmachine frame 2 having, arranged in the throat thereof, a workpiecesupport in the form of a workpiece table 3 which serves to support aworkpiece, e.g., a metal sheet 4, which is to be processed. Theworkpiece table 3 defines a horizontal support plane 5 for the metalsheet 4 to be processed. The support plane 5 extends parallel to the x/yplane of the coordinate system shown in FIG. 1. By means of a coordinateguide 6, the metal sheet 4, which is clamped in position by means ofclamps 7, is movable in the support plane 5 of the workpiece table 3.

A tool punch holder 8 is arranged at a front end of an upper arm of theC-shaped machine frame 2. The tool punch holder 8 is configured tosupport a tool punch 9. A tool die holder 10 is arranged at a front endof a lower arm of the C-shaped machine frame 2. The tool die holder 10is configured to support a tool die 11. The tool punch 9 and the tooldie 11 form a tool 12 for processing the metal sheet 4 by cutting and/orforming.

The punching/forming machine 1 also includes a drive unit for drivingthe tool punch holder 8 and the tool die holder 10. The drive unitincludes a punch drive 13 and a die drive 14 in the form of lineardrives. The tool punch holder 8, together with the supported tool punch9, can be raised and lowered relative to the workpiece table 3 along astroke axis 15 via the punch drive 13. In a comparable manner, the tooldie holder 10, together with the supported tool die 11, can be raisedand lowered relative to the workpiece table 3 along the stroke axis 15by means of the die drive 14. In addition, the tool punch holder 8 andthe tool die holder 10 can be adjusted with regard to their rotationalposition about a tool rotation axis 16, which is identical to the strokeaxis 15, by means of a tool turning drive.

A linear magazine 17 with further tools 12 is provided on the coordinateguide 6. The tools 12 situated in the linear magazine 17 are each heldby a tool cassette 18 and can each be secured to the tool punch holder 8and the tool die holder 10 as required for processing of the metal sheet4.

During tool-changing and during processing of a workpiece, all of thedrives of the punching/forming machine 1 are controlled by means of anumerical control unit 21. The numerical control unit 21 can includestorage means 19 (e.g., memory storage) for storing data associated withthe workpiece 4 and/or the tool 12, and control means 20 (e.g., aprocessor) for calculating and controlling the raising, lowering androtational movements of the tool punch holder 8 and the raising,lowering and rotational movements of the tool die holder 10 based, atleast in part, on the data stored on the storage means 19.

FIGS. 2 a-c illustrate a procedure for punching the workpiece 4 in aregion of a groove-like formed shape 22 projecting upwards beyond thesupport plane 5. The formed shape 22 has been produced in the workpiece4 in a previous step by roll-forming using a forming tool which, asexplained above, has subsequently been replaced by the punching tool 9,11 shown in FIGS. 2 a-c.

As indicated by an arrow in FIG. 2 a, for processing by punching theworkpiece 4 is first moved in the support plane 5 of the workpiece table3 by means of the coordinate guide 6 until the region of the formedshape 22 that is to be processed by punching is positioned above the die11. During that movement, the pyramidal or conical die 11 is in a homeposition R in the Z-direction (direction of gravity) in which a supportface 23 formed on the top surface of the die 11 is flush with theworkpiece plane 5. The tool punch 9 also adopts here a home position Rabove the workpiece support 5.

As shown in FIG. 2 b, the die 11 is subsequently raised until it reachesa processing position B in the Z-direction, at which the support face 23of the die 11 reaches the underside of a flat region on the formed shape22, which region is to be processed. The tool die 11 is positioned inthe processing position B by the control unit 21, i.e., the movementalong the stroke axis 15 is stopped as soon as the support face 23reaches the underside of the formed shape 22. The attainment of theprocessing position B by the die 11, or by the support face 23, can bedetected via a sensor unit 26 of the punching/forming machine 1 (FIG.1), for example by means of pressure sensors or optical sensors, but itis also possible for the control unit 21 to specify the stroke of thetool die 11 required to attain the processing position B on the basis ofthe known data on the formed shape of the workpiece 4, without theassistance of sensors.

As can also be seen in FIG. 2 b, the die 11 can be matched to thegeometry of the formed shape 22 in such a way that it can be raisedabove the workpiece plane 3 without this resulting in a collision withthe workpiece 4 before the die 11 reaches the processing position B. Inthis regard, both the size of the support face 23 and also the angleformed by a lateral surface 25 of the die 11 and the support face 23 orthe plane 5 of the metal sheet (in the present case approximately 45°,typically between approximately 20°and approximately 80°) can beselected such that the lateral surface 25 of the die 11 does not collidewith the peripheral regions of the formed shape 22 before the supportface 23 reaches that region of the formed shape 22 that is to beprocessed. A tool 12 suitable for processing a given formed shape 22 canbe selected from the linear magazine 17 by the control unit 21 and canbe secured in the tool die holder 10 and the tool punch holder 8 asdescribed above.

Punching is then carried out on the region of the formed shape 22resting on the support face 23 in the processing position B by loweringthe punch 9 onto the die 11 and in so doing bringing it into engagementwith an aperture 24 provided at the support face 23 (FIG. 2 c). Afterprocessing by punching, in which the punch 9 may also process theworkpiece 4 with a plurality of punching strokes, the die 11 may bereturned to the home position R shown in FIG. 2 a in order for theworkpiece 4 to be processed at a different place.

It is not imperative for the die 11 to be positioned in the processingposition B. In cases where further upward or downward forming operationsare to be performed on the region to be processed, the die 11 can beraised and, at the same time, the tool punch 9 can be lowered in orderfor the workpiece 4 to be formed above the workpiece support 3.

FIGS. 3 a-c show a processing operation being performed on a workpiece 4in which, in contrast to the workpiece 4 shown in FIGS. 2 a-c, theformed shape does not project upwards but projects downwards beyond thesupport plane 5 of the workpiece 4. Referring to FIG. 3 a, for example,the support plane 5 of the workpiece 4 is formed by the top surface of abristle carpet 3 a formed on the processing table 3, the bristles ofwhich are bent down to provide the necessary room for the formed shape22 when the workpiece 4 is being moved in the support plane 5 by meansof the coordinate guide 6. The processing operation otherwise proceedsanalogously to the processing operation described in FIGS. 2 a-c, withthe difference that the processing position B is not above the supportplane 5 in the workpiece support 3, but is below it, so that the punch 9is moved below the support plane 5 in order for the formed shape 22 tobe processed. In that operation, a punch shank 9 a, with which the punchis supported on the tool punch holder 8 (FIG. 1), remains above thesupport plane 5 to allow the punch head, or rather its cutting edge,formed on the punch 9 to be engaged by the formed shape 22 without thepunch shaft 9 a acting as an obstructing contour.

In addition to the formed shapes shown in FIGS. 2 a-c and FIGS. 3 a-c inthe form of a groove, as are typically produced by roll-forming, other,for example gill-like louver, formed shapes can be made in the workpiece4 by suitable forming tools. Such formed shapes also may be processedabove or below the workpiece plane 5 in the manner described above. Allin all, processing by punching and/or forming may be performed in themanner described above with high precision also in upwardly formed ordownwardly formed regions of a workpiece. In some cases, the role ofpunch 9 and die 11 may be interchanged as compared with the arrangementshown in FIGS. 2 a-c and FIG. 3 a-c, such that the punch 9 is disposedbelow and the die 11 is disposed above the support plane 5.

A number of embodiments of the invention have been described.Nevertheless, it will be understood that various modifications may bemade without departing from the spirit and scope of the invention.Accordingly, other embodiments are within the scope of the followingclaims.

1. A method of processing a plate workpiece, the method comprising:supporting the plate workpiece on a workpiece support; forming a formedshape in the plate workpiece while the plate workpiece is supported onthe workpiece support using a forming tool, the formed shape extendingupwardly or downwardly from a support plane of the workpiece support,the forming tool being secured to a tool die holder and a tool punchholder, the tool die holder and the tool punch holder being tool holdersto which different tools can be secured; replacing the forming tool witha punching tool, the punching tool comprising a tool die and a toolpunch, the tool die being secured to the tool die holder and the toolpunch being secured to the tool punch holder; and after replacing theforming tool with the punching tool, moving the tool die and the toolpunch of the punching tool along a stroke axis, toward a processingposition above or below the support plane, and into contact with theplate workpiece in a region of the formed shape, thereby processing theplate workpiece in the region of the formed shape.
 2. The method ofclaim 1, wherein forming the formed shape in the plate workpiececomprises roll-forming the formed shape.
 3. The method of claim 1,further comprising, following the forming of the formed shape, movingthe plate workpiece along the support plane toward a position in whichthe formed shape intersects the stroke axis.
 4. The method of claim 1,further comprising moving the tool punch and the tool die to a homeposition in which the tool die does not project upwards beyond thesupport plane and the tool punch does not project downwards beyond thesupport plane.
 5. The method of claim 1, wherein the tool die issupported in the tool die holder and the tool punch is supported in thetool punch holder, and wherein moving the tool die and the tool punchalong the stroke axis comprises moving the tool die holder and the toolpunch holder along the stroke axis.
 6. The method of claim 1, whereinmoving the tool die and the tool punch along the stroke axis comprisesmoving the tool die and the tool punch independently of each other alongthe stroke axis.
 7. The method of claim 1, further comprising detectingthe presence of the tool die in the processing position.
 8. The methodof claim 1, further comprising moving the plate workpiece along thesupport plane toward a position in which the formed shape intersects thestroke axis.
 9. The method of claim 8, wherein the movement of the plateworkpiece is carried out by a coordinate guide.
 10. The method of claim1, further comprising: selecting the tool punch and the tool die,wherein the tool punch and the tool die are matched to a geometry of theformed shape of the plate workpiece; and before processing the plateworkpiece in the region of the formed shape, securing the selected toolpunch to the tool punch holder, and securing the selected tool die tothe tool die holder.